Prof. Dr. Rainer Hedrich (Molecular Plant Physiology & Biophysics, Wuerzburg University, Germany)

2017. 06. 30 (Fri) 11:00 ~ 12:30

Seminar Room 1, Myodaiji (132-134)　

Lab. Evol. Biol. Mitsuyasu Hasebe (7546)

Charles Darwin over 100 years ago recognized that the Venus flytrap Dionaea muscipula living on nutrient poor soil is capturing animals. When small animals visit the trap surface and touch the trigger hairs the trap gets excited and after firing two action potentials closes. Trying to escape the encaged prey keeps on exciting the capture organ and thereby glands covering the inner trap surface trigger secretion of a digestive fluid. During prey decomposition the animal-derived nutrients are ingested. Although the concept of botanical carnivory is known since Darwin’s time, due to the entire lack of genomic information, the molecular processes providing for animal feeding remain still unknown.

To bridge that gap, we sequenced the genome together with transcriptome expressed in different organs of Dionaea and assembled a backbone transcriptome of the carnivorous plant. Given that with Dionaea leaves only the bi-lobed tip but not the petiole develop into a sophisticated capture organ, we focused on trap genes that become active upon contact with the animal victim. Special attention we gave to trigger hairs and glands engaged with i) generation of the action potential, ii) secretion of hydrolases, and iii) uptake of nutrients extracted from the digested animal. Serving the latter function, we spotted ion channels and transporter. Following expression of the Dionaea gland-expressed nutrient transporter genes in Xenopus oocytes, ion selective voltage changes and currents were recorded. Our studies indicate that Dionaea glands operate selective, high capacity channels and transporters to provide nutrients and osmotic potential while the feeding on a decomposing victim.

During the seminar the molecular nature and mechanism of the hunting cycle of the most exciting green carnivore will be discussed.